Gattendorfia costata Vöhringer, 1960

Korn, Dieter & Weyer, Dieter, 2023, The ammonoids from the Gattendorfia Limestone of Oberrödinghausen (Early Carboniferous; Rhenish Mountains, Germany), European Journal of Taxonomy 882, pp. 1-230 : 130-131

Gattendorfia costata Vöhringer, 1960

Fig. 76 ; Table 74

Gattendorfia costata Vöhringer, 1960: 152 , pl. 5 fig. 7.

Gattendorfia costata – Bartzsch & Weyer 1982: 19, text-fig. 4.2. — Korn 1994: 73, text-fig. 65c.

non Gattendorfia costata Vöhringer 1960: 152 , text-figs 27, 37 (only). — Weyer 1977: 173, pl. 1 figs 1, 7. — House 1985a: 126, pl. 6.7.14 fig. d. — Gordon 1986: 18, text-figs 6.1–6.3, 8.3. — Korn 1994: 73, text-figs 66d, 67a (only). — Dzik 1997: 107, text-fig. 28f. — Korn & Weyer 2003: 100, text-fig. 14h–i. — Korn et al. 2003b: 1125, text-fig. 3b. — Sprey 2002: pl. 4 fig. 7.

Diagnosis

Species of Gattendorfia with a conch reaching 50 mm diameter. Conch at 30 mm dm thickly pachyconic, evolute (ww/dm ~0.80; uw/dm ~0.45). Whorl profile at 30 mm dm extremely depressed (ww/wh ~2.85); coiling rate very low (WER ~1.48). Venter broadly rounded, umbilical margin narrowly rounded. Without constrictions on the shell surface and without internal shell thickenings, with short ribs on the umbilical margin.

Material examined

Holotype

GERMANY • Rhenish Mountains, Oberrödinghausen , railway cutting ; Hangenberg Limestone , bed 2; Vöhringer Coll.; illustrated by ( Vöhringer 1960: pl. 5 fig. 7), Korn (1994: text-fig. 65c) and Sprey (2002: pl. 4 fig. 7); re-illustrated here in Fig. 76 ; GPIT-PV-63941.

Description

Holotype GPIT-PV-63941 is a rather poorly preserved specimen with 32 mm diameter of the conch ( Fig. 76 ). It is partly ground and therefore shows hardly any remains of the shell. The conch is barrelshaped (ww/dm = 0.84) with a very broadly rounded venter, a rather narrowly rounded umbilical margin and a convex umbilical wall. The umbilicus is rather wide (uw/dm = 0.44) and the coiling rate is very low (WER = 1.49). Little can be said about the ornament; short, blunt riblets are formed on the umbilical margin.

Remarks

Vöhringer (1960) merged at least three morphological easily distinguishable species under the name Gattendorfia costata . (1) The first of these, defined by the holotype, is characterised by a wide umbilicus (uw/dm ~0.45) and weak nodes on the raised umbilical margin. (2) The second of these species, described here as G. corpulenta sp. nov., has a much narrower umbilicus with a uw/dm ratio of ~0.30, such as the cross section which he published ( Vöhringer 1960: text-fig. 27) and short backwardly directed ribs. (3) The third, not explicitly mentioned by Vöhringer (1960) and described here as Zadelsdorfia oblita sp. nov., also has a much narrower umbilicus (uw/dm = 0.30) and lacks ribs but possesses concavo-convex internal shell thickenings. Another separating criterion to distinguish between G. costata and G. corpulenta is the course of the constrictions, which are concavo-convex with a ventrolateral projection and a rather narrow ventral sinus in G. costata but with convex course without ventrolateral projection and with broad ventral sinus in the new species G. corpulenta .

Figures

Fig. 76. Gattendorfia costata Vöhringer, 1960 from the Oberrödinghausen railway cutting; photographs and dorsal view reconstruction of holotype GPIT-PV-63941 (Vöhringer Coll.) from bed 2. Scale bar units =1 mm.

Tables

Table 74. Conch measurements, ratios and rates of Gattendorfia costata Vöhringer, 1960 from Oberrödinghausen.

specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
GPIT-PV-63941	31.7	26.8	9.6	14.1	5.7	0.84	2.79	0.44	1.49	0.40